x COLOURS AND ORNAMENTS CHARACTERISTIC OF SEX 281 
not require special protective coloration, such as many of 
the birds of prey, the larger waders, and the oceanic birds. 
There are a few very curious cases in which the female 
bird is actually more brilliant than the male, and which yet 
have open nests. Such are the dotterel (Eudromias morinel- 
lus), several species of phalarope, an Australian creeper 
(Climacteris erythropus), and a few others; but in every one 
of these cases the relation of the sexes in regard to nidification 
is reversed, the male performing the duties of incubation, 
while the female is the stronger and more pugnacious. This 
curious case, therefore, quite accords with the general law of 
coloration. 1 
Sexual Colours of other Vertebrates. 
We may consider a few of the cases of sexual colouring of 
other classes of vertebrates, as given by Mr. Darwin. In 
fishes, though the sexes arc usually alike, there are several 
species in which the males are more brightly coloured, and 
have more elongated fins, spines, or other appendages, and in 
some few cases the colours are decidedly different. The males 
often fight together, and are altogether more vivacious and 
excitable than the females during the breeding season ; and 
with this we may connect a greater intensity of coloration. 
In frogs and toads the colours are usually alike, or a little 
more intense m the males, and the same may be said of most 
snakes. It is in lizards that we first meet with considerable 
sexual differences, many of the species having gular pouches, 
frills, dorsal crests, or horns, either confined to the males, or 
more developed in them than in the females, and these orna¬ 
ments are often brightly coloured. In most cases, however, 
the tints of lizards are protective, the male being usually a 
little more intense in coloration ; and the difference in extreme 
cases may be partly due to the need of protection for the 
female, which, when laden with eggs, must be less active and 
less able to escape from enemies than the male, and may, 
therefore, have retained more protective colours, as so many 
insects and birds have certainly done. 2 
In mammalia there is often a somewhat greater intensity 
1 Seebohm’s History of British Birds, vol. ii., introduction, p. xiii. 
2 For details see Darwin’s Descent of Man , chap, xii, 
